database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-19 13:42:17 +03:00
Code Activity

Teach planner about more monotonic window functions

Browse Source 
9d9c02ccd introduced runConditions for window functions to allow
monotonic window function evaluation to be made more efficient when the
window function value went beyond some value that it would never go back
from due to its monotonic nature.  That commit added prosupport functions
to inform the planner that row_number(), rank(), dense_rank() and some
forms of count(*) were monotonic.  Here we add support for ntile(),
cume_dist() and percent_rank().

Reviewed-by: Melanie Plageman
Discussion: https://postgr.es/m/CAApHDvqR+VqB8s+xR-24bzJbU8xyFrBszJ17qKgECf7cWxLCaA@mail.gmail.com
This commit is contained in:
David Rowley
2023-01-27 16:08:41 +13:00
parent 783d8abc3b
commit 456fa635a9
3 changed files with 50 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
src/backend/utils/adt/windowfuncs.c
View File

@@ -288,6 +288,15 @@ window_percent_rank_support(PG_FUNCTION_ARGS)
{
Node *rawreq = (Node *) PG_GETARG_POINTER(0);
if (IsA(rawreq, SupportRequestWFuncMonotonic))
{
SupportRequestWFuncMonotonic *req = (SupportRequestWFuncMonotonic *) rawreq;
/* percent_rank() is monotonically increasing */
req->monotonic = MONOTONICFUNC_INCREASING;
PG_RETURN_POINTER(req);
}
if (IsA(rawreq, SupportRequestOptimizeWindowClause))
{
SupportRequestOptimizeWindowClause *req = (SupportRequestOptimizeWindowClause *) rawreq;
@@ -362,6 +371,15 @@ window_cume_dist_support(PG_FUNCTION_ARGS)
{
Node *rawreq = (Node *) PG_GETARG_POINTER(0);
if (IsA(rawreq, SupportRequestWFuncMonotonic))
{
SupportRequestWFuncMonotonic *req = (SupportRequestWFuncMonotonic *) rawreq;
/* cume_dist() is monotonically increasing */
req->monotonic = MONOTONICFUNC_INCREASING;
PG_RETURN_POINTER(req);
}
if (IsA(rawreq, SupportRequestOptimizeWindowClause))
{
SupportRequestOptimizeWindowClause *req = (SupportRequestOptimizeWindowClause *) rawreq;
@@ -465,6 +483,18 @@ window_ntile_support(PG_FUNCTION_ARGS)
{
Node *rawreq = (Node *) PG_GETARG_POINTER(0);
if (IsA(rawreq, SupportRequestWFuncMonotonic))
{
SupportRequestWFuncMonotonic *req = (SupportRequestWFuncMonotonic *) rawreq;
/*
* ntile() is monotonically increasing as the number of buckets cannot
* change after the first call
*/
req->monotonic = MONOTONICFUNC_INCREASING;
PG_RETURN_POINTER(req);
}
if (IsA(rawreq, SupportRequestOptimizeWindowClause))
{
SupportRequestOptimizeWindowClause *req = (SupportRequestOptimizeWindowClause *) rawreq;